To explore the clinical application of genetic analysis combined with Western blotting in the identification of the pathogenicity of novel mutations in ACADVL gene of very long chain acyl-CoA dehydrogenase deficiency (VLCADD).

From June 1, 2017 to October 31, 2020, 290 738 blood samples from newborns screened in Nanjing Neonatal Disease Screening Center were analysed. Among them, 4 newborns were suspected of VLCADD by tandem mass spectrometry. Peripheral blood was collected from the 4 newborns and their families for gene analysis, and the expression of very long chain acyl-CoA dehydrogenase (VLCAD, ACADVL) in peripheral blood was detected by Western blotting.

Four children were diagnosed as VLCADD through gene analysis, and 8 mutation sites were detected: 2 likely pathogenic variants (c.664 G>C、c.342+ 1 G>A), 5 novel variants (c.694 G>A、c.1699 C>T、c.1030 A>G、c.1247 C>T、c.833_835 del), and 1 site was the first report (c.1077+ 6 T>A). A total of 12 peripheral blood samples from the 4 families were collected to detect the expression of ACADVL protein by Western blotting. The results confirmed that the target protein expressions of the 4 patients were significantly lower than those of their parents. The storage time of the peripheral blood samples in family 1 was longer than that of other three families, accordingly the ACADVL protein level in family 1 were significantly lower than that of other three families. Compared with family 1, non-VLCADD family 5 with the same storage time of peripheral blood, the decrease of internal reference ACTIN protein was more obvious.

When the detection site of ACADVL gene in children with suspected VLCADD is of unclear clinical significance, it is recommended to use fresh peripheral blood samples to detect the ACADVL protein by Western blotting, the results of which can be complementary with the genetic results.